Stepper-friendly macros: clarification

Hi David, List
> I haven't ever tried using an alternative debugger on Lisp code
Maybe I didn't state this clear. I'm not talking about alternative
stepper. I only talk about small additional feature which (I hope) can
be added to existing stepper. Sometimes you want to see macroexpanded
code, that's ok. Sometimes (e.g. with "iterate") you would not want to
see messy macroexpanded code, but might want just to set a breakpoint
at some clause and stop at it at the beginning of every iteration. My
goal is to enable macro writer to tell IDE which points are "stepable"
and to what place in macroexpanded source they correspond. This would
not disable ability of seeing macroexpanded code, but would add a
choice which is very convinient.

Small example:

(defmacro breakpointable (x) x)
(defun f1 ()  (breakpointable
     (   ; one can set breakpoint here
    + 2 2 )))

(defmacro non-breakpointable (x) (copy-tree x))
; Any macro where source code is copied
; instead of splicing, would lead to
; source position loss. 'iterate' is one example

(defun f2 () (non-breakpointable
     (   ; can't set breakpoint here as source was copied
    + 2 2 )))


(defmacro assign-source (literal expanded)
  "Assigns a literal source place for expanded code place.
  Think of it as a kind of #line cpp directive for stepper"
  `(setf (car ,literal) (car ,expanded)
         (cdr ,literal) (cdr ,expanded)
         ,expanded ,literal))

(defmacro breakpointable-again (x)
  (let ((result (copy-tree x)))
     (assign-source x result)
     result))

(defun f3 ()
  (breakpointable-again
     (  ; can set a breakpoint
      + 2 2)))

In this example, all works fine, but there is a problem: literal
source is modified.
Indeed in some cases this approach does not work with "iterate".
My suggestion is to add one macro, "assign-source", but with correct
definition, which does not smash literal data. I was unable to write one, as
I have no access to lispworks-tools source.

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Re: Stepper-friendly macros: clarification

Unable to parse email body. Email id is 12183

Re: Stepper-friendly macros: clarification

> we will add an operator something like this:
Thanks, that's very fine :-))

2013/3/8, Martin Simmons <martin@lispworks.com>:
>
>>>>>> On Sun, 3 Mar 2013 21:31:38 +0400, Denis Budyak said:
>>
>> Hi David, List
>> > I haven't ever tried using an alternative debugger on Lisp code
>> Maybe I didn't state this clear. I'm not talking about alternative
>> stepper. I only talk about small additional feature which (I hope) can
>> be added to existing stepper. Sometimes you want to see macroexpanded
>> code, that's ok. Sometimes (e.g. with "iterate") you would not want to
>> see messy macroexpanded code, but might want just to set a breakpoint
>> at some clause and stop at it at the beginning of every iteration. My
>> goal is to enable macro writer to tell IDE which points are "stepable"
>> and to what place in macroexpanded source they correspond. This would
>> not disable ability of seeing macroexpanded code, but would add a
>> choice which is very convinient.
>>
>> Small example:
>>
>> (defmacro breakpointable (x) x)
>> (defun f1 ()  (breakpointable
>>      (   ; one can set breakpoint here
>>     + 2 2 )))
>>
>> (defmacro non-breakpointable (x) (copy-tree x))
>> ; Any macro where source code is copied
>> ; instead of splicing, would lead to
>> ; source position loss. 'iterate' is one example
>>
>> (defun f2 () (non-breakpointable
>>      (   ; can't set breakpoint here as source was copied
>>     + 2 2 )))
>>
>>
>> (defmacro assign-source (literal expanded)
>>   "Assigns a literal source place for expanded code place.
>>   Think of it as a kind of #line cpp directive for stepper"
>>   `(setf (car ,literal) (car ,expanded)
>>          (cdr ,literal) (cdr ,expanded)
>>          ,expanded ,literal))
>>
>> (defmacro breakpointable-again (x)
>>   (let ((result (copy-tree x)))
>>      (assign-source x result)
>>      result))
>>
>> (defun f3 ()
>>   (breakpointable-again
>>      (  ; can set a breakpoint
>>       + 2 2)))
>>
>> In this example, all works fine, but there is a problem: literal
>> source is modified.
>> Indeed in some cases this approach does not work with "iterate".
>> My suggestion is to add one macro, "assign-source", but with correct
>> definition, which does not smash literal data. I was unable to write one,
>> as
>
> Thanks for the suggestion -- we will add an operator something like this:
>
> (dspec:replacement-source-form original-form new-form)
>
> which can be wrapped around copied code to indicate the original form.
> E.g. walk-expr in iterate would return
>
> `(dspec:replacement-source-form ,expr ,(prognify body))
>
> --
> Martin Simmons
> LispWorks Ltd
> http://www.lispworks.com/
>
> _______________________________________________
> Lisp Hug - the mailing list for LispWorks users
> lisp-hug@lispworks.com
> http://www.lispworks.com/support/lisp-hug.html
>
>

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